| In the rigid mechanism,the deviation of motion trajectory caused by the auxiliary clearance and the impact of the joint collision seriously affect the working performance and service life of the mechanism.Especially rigid vibration isolation mechanisms not only cannot block the external excitation correctly,but also generate its own The secondary impact is transmitted to the mechanical system.The use of a flexible hinge to replace the compliant mechanism of traditional motion pairs can effectively reduce the impact of this aspect,and correctly transmit motion and force.Among them,the LET plane flexible hinge(Lamina emergent torsional)is a new type of flexible hinge that is made of two-dimensional metal sheet plane processing and realizes three-dimensional movement,which further simplifies the structure while enjoying the advantages of the traditional flexible hinge.At present,the research on the new flexible hinge focuses on the realization of a single rotating pair and the optimization of its structural performance.The traditional flexible design method is still adopted for the multi-degree-of-freedom motion pair.There is no integrated lightweight multi-freedom hinge solution.Therefore,it is necessary to carry out further research work on a new type of plane flexible hinge with multiple degrees of freedom.In this paper,two new types of planar flexible hinge is researched,and the research work on the configuration design,dynamic stiffness and motion characteristics of the new hinge has been carried out,including:(1)Aiming at the problem that plane flexible hinges are mostly single-degreeof-freedom rotation pairs,a new type of plane flexible Hooke hinge is proposed by expanding the LET hinge movement form;the flexibility of the Hooke hinge is verified by the comparison of the flexibility of the hinges in all directions.The degree of rotational freedom;establishes the theoretical calculation model of the equivalent stiffness of the hinge dynamics;reveals the nonlinear stiffness variation law under large deformation by a large number of repeated simulation experiments,and gives approximate theoretical formulas by means of Gauss fitting;Based on the influence of structural parameters on the change of hinge stiffness,the working performance characteristics of plane flexible hook hinges are discussed,which provides a theoretical basis for the further application of hinges.(2)In order to integrate the degree of freedom of the existing flexible spherical joint scheme,and to realize the original spherical joint working mode in a composite deformation manner,a plane flexible spherical joint with equivalent spherical joint movement is proposed;The deformation conditions are analyzed,and the theoretical calculation formula for the equivalent stiffness of the hinge is deduced.The hinge structure is further optimized for the case where the hinge fluctuates greatly under different working angles.The optimization results show that three spiral foil combinations are used.Under the new structure,the variance of the combined stiffness value is very small,the stiffness stiffness is stable,and it is the closest to the working characteristics of the original ball hinge.(3)Two planar flexible hinges designed in this study were introduced into the Stewart platform to form a new 6DOF parallel vibration isolation platform.The rigidflexible coupling dynamics of the new platform was analyzed using ADAMS and ANSYS co-simulation,and the transmission rate of the new platform was passed.The analysis shows that the new platform is working properly,and the movement state of the designed hinge in the application is consistent with the theoretical analysis and meets the requirements for use.At the same time,compared with the original rigid hinge with motion gap,it is verified that the plane compliant hinge can effectively avoid the influence of abrupt change of transmission rate caused by rigid hinge movement gap while meeting the motion requirements. |
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